We welcome the comments provided by Dr. Burns. As noted in our article,1 a limitation of our approach is that a smoker's level of exposure to the toxic chemicals in cigarette smoke is influenced by both the chemistry of the cigarette smoke and the way the cigarette is smoked. We recognize that to successfully claim reductions in exposure or risk, changes in tobacco product emissions have to be documented with changes in exposure levels in smokers or reduced rates of tobacco-related diseases.
New research has found only a weak relation between biomarker levels and smoking machine-derived smoke yields.2,3 Further, it is not yet known what level of change in smoke emissions or exposure is needed to measurably reduce the toxicity of smoked tobacco products. Recognizing the complexity of the tobacco product-exposure-disease framework, any systematic monitoring of smoke emissions provides information on a factor relevant to understanding the harms caused by tobacco. The absence of this type of data clearly prevented the scientific community from reaching an earlier understanding of factors underlying changing patterns of lung cancer histology among cigarette smokers.
We consider the revised developmental Healthy People 2010 objective 27-20 as the start of a process to reach an overall goal of understanding and reducing population-level exposures to toxic chemicals in cigarette smoke. To strengthen the surveillance of how cigarettes adversely affect public health, future revisions to the objective will draw upon the strongest available evidence by considering measures of exposure, addiction, and other tobacco-related morbidities.